1. Field of the Invention
The present invention relates to grilles for air conditioning which are installed in car interiors.
2. Description of the Related Art
As an example of a conventional grille for air conditioning which is installed mainly on the instrument panel provided inside a car, a grille, which is about to be described, is known (Japanese Utility Model Laid-open No. 51-2849). In this grille, the wind direction adjusting plates are made of leaf springs. These wind direction adjusting plates are mounted inside a case such that each plate curves to form a circular arc. Then, by applying a force on these wind direction adjusting plates with an operating lever to change the curving direction of the wind direction adjusting plates either to the right or to the left, the direction of the wind being blown can be made to vary accordingly.
As an example of these wind direction adjusting plates, there is a type wherein a V-shaped slit is formed on the upper and lower surfaces of each wind direction adjusting plate to make it curve easily (Japanese Utility Model Laid-open No. 51-6643).
However, in the conventional grille for air conditioning mentioned above, in order to change the direction of the wind by changing the curving direction of the wind direction adjusting plates with the operating lever, depending on the position of the operating lever and because of the elastic forces acting on the wind direction adjusting plates, a considerable amount of operating force was needed. Also, when the wind direction adjusting plates were made to curve, since these wind direction adjusting plates are capable of curving naturally, there have been cases where these wind direction adjusting plates became twisted or distorted.
Further, when the strength and hardness of the various pieces were increased and the accuracy of the bearings and others were improved in order to solve the problems mentioned above, there arose the problems of greater weight of the grille for air conditioning as a whole and higher manufacturing costs.
Also, in the grille for air conditioning mentioned above, aside from the fact that the structure was complicated, there was the problem of the wind direction adjusting plates' not curving in a smooth manner. Further, there was the problem of noise being generated when a specially strong wind was being blown, because the end portions of the wind direction adjusting plates positioned at the location where the wind was being introduced were not aligned in the same direction as that of the coming wind.
Also, there have been cases wherein the wind direction adjusting plates became twisted because the pressure from the operating lever, that is used for changing the direction of the wind, is not transmitted evenly to the whole set of wind direction adjusting plates, causing the flow of the wind to become uneven and an air eddy to be generated. As a result, noise was generated, and the direction of the wind did not blow in the desired direction. And, also because of the irregularity of the slits mentioned earlier, noise was generated, and the direction of the wind did not blow in the desired direction.
Further, because an operating force, aside from the frictional forces that act on the bearings of the wind direction adjusting plates, and others, is needed to cause the elastic deformation of the wind direction adjusting plates, the required operating force becomes greater as the amount of curvature of the wind direction adjusting plates becomes larger.
Finally, when the wind direction adjusting plates were made to curve further by means of the operating lever, and the frictional forces on the bearings, and others, of the wind direction adjusting plates were small, there have been cases wherein the wind direction adjusting plates returned to their original state, that is, to their straight positions, because of the elastic forces acting on the wind direction adjusting plates themselves.